Superintendent Dr. Jill Kingsfield announced the postponement Tuesday afternoon. She said the graduation was postponed due to "extenuating circumstances surrounding the past 48 hours."
Dr. Kingsfield did not reveal any specifics about the extenuating circumstances, but the announcement came one day after threats against the school were posted on social media.
"I was looking forward to graduation, I had a lot of family members from out of town come in," said Quincy Cobbs, senior and Argo basketball player.
He'll have to wait a little longer to get his diploma.
"I'm OK with it because of my safety," he said. "We still don't know when graduation is going to be yet, though."
"We are going to just wait for the weekend and celebrate that way," said Aquila Shelby, Quincy's mother.
Shelby was one of several parents to call Summit police after a random message appeared on Snapchat over the weekend. The threat read, "I myself will be shooting every class at Argo Community High School so if you come you are a target."
School officials said on Monday, police arrested the person who made that Snapchat threat.
Then Tuesday, a second threat came late in the day, forcing administrators to postpone graduation.
Kingsfield said Summit police confirmed a juvenile from Joliet was identified as the person associated with the second threat, and that the juvenile had been taken into custody. Charges were pending, she said.
She said the juvenile was not a viable threat and had no connections to the Argo community.
"It was disappointing," Shelby said. "I think the school made the right decision, but it was disappointing to hear at the last minute that the graduation was cancelled."
Kingsfield said there is no immediate threat to the school. She said the graduation ceremony will be rescheduled.